Tag Archives: varroa destructor

I’ve stopped worrying about killing the vector and started killing the pathogen.

08 Monday Apr 2024

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The story starts years ago when I noticed that the bees flew with more enthusiasm and worked harder in the days following a varroa mite treatment (oxalic acid vaporization). I asked others if they too saw this behavior change. Some said they never took notice; others said it was obvious. Years later I measured the coming and going on the landing board using one of those click counters. It was true; the bees were energized after a treatment. But I didn’t have the answer as to why. Last summer I spoke to someone more knowledgeable than I in entomology and he used the analogy, “Have you ever noticed how good a dog feels the day after a flea dip?” A great reply that satisfied me for awhile. But I thought, putting a dent in a 3% mite load (not even eliminating the mites) couldn’t increase the entire colony’s enthusiasm as evidenced with the increase in activity on the landing board. Could it? Or was something else going on? But I’m getting ahead of myself.

Back in 2021, I started doing some research and learned that the EPA first approved oxalic acid (OA) in 1957 as a disinfectant in bathrooms and septic systems among other uses. It’s still used today in cleaning solutions for industry food production machines, not to mention good old Bar Keeper’s Friend. If you’re not sure of the definition of disinfectant look it up. It’s different than sanitizer, cleaner, or antibacterial. So, is OA also acting in that manner in the hive? Is it giving the internal surfaces of the hive and the bees a chemical scrubbing? Am I killing bacteria and viruses as well as mites? I didn’t know but I wanted to try a few things.

Over two years ago (January 2022) I started treating my bee hives routinely with OA vapor. That’s “routine schedule” as meaning a set date each month to treat on my calendar. Similar to you taking an antibiotic on a routine schedule, or a medicine for a chronic condition like hypertension, diabetes, or reflux. Consider it an IPM treatment for treating mites and accompaning viruses. Also included in my goals were to 1) decrease the number of yearly OA treatments and 2) reduce the likelihood of resistance to OA. But simply put, all I was actually doing was going to be changing one aspect of treatment – the dosing schedule from one that targeted the mites’ reproductive schedule, to one that disinfected the colony’s environment regularly. Of course, any varroa mites killed would be a value-added outcome.

That year I did not suffer any colony losses during the spring, and I made more honey than usual. However, I did have some colony failures (~ 10%), as is typical, after the nectar flow during our dearth period. Multiple stressors (SHB, harvest, and climbing mite to bee ratios) take their toll during this period as the mite load climbs, increasing the viral load. I intervened with a single series of OA treatments and the losses stopped, leading me to believe the stressor most critical is mite/viral load. After completing the single series of treatments, I resumed my scheduled monthly treatments as before and had no winter losses. After the first year, I tried to make sense of that year’s interventions and outcomes and develop a plan for next year.

In January 2023, I continued my routine treatment schedule and, as experienced the previous year, I had no losses during the nectar flow. But this year I decided to make a change to the dosing schedule during the post nectar flow time period. I changed to a once every two-week treatment schedule (actually on the 1st and 15th) and continued this schedule until fall – so that would be twice monthly treatments June – October. This added about 5 additional treatments to the year which pushed me to the edge on my goal to limit the number of treatments per year. In November, I resumed the routine monthly schedule. This scheduling model resulted in no colony losses in the spring, fall, summer, or winter of 2023. My honey production was about 65 lbs. per hive which is about 50% higher than expected in the SC Midlands. Keeping bees healthy during the nectar flow keeps them working harder rather than our current method of allowing the bees’ health to decline over the season and often collapse just prior to treatment salvation.

All this brings me to this year (2024). So far, I have not sustained any mite/virus related losses. Coming out of winter I saw the occasional weak colony, needing a new queen, or help with SHBs. But my hives built up quickly in the pre-season. I just did my accounting for taxes and used less sugar last year having left more honey due to their productivity (and my reluctance to pay for sugar). My point is they are healthy and handling stressors.

Recently I spent some time researching organic acids as disinfectants, antimicrobials, etc. There are some studies on this with viruses. Yes, organic acids can be antivirals. It is dose and pH dependent to some extent. OA is around 2 on the pH scale so it’s potent. But there are some unidentified factors as well. For instance, acetic acid sometimes is more effective with certain viruses than acids with lower pH. So, the reason organic acids (and which) kill viruses still is somewhat a mystery.

Why is this interesting? First, because it shouldn’t be working. One would think my colonies would be mite ridden and failing. This OA dosing schedule should be allowing the mites too much freedom to reproduce. However, I haven’t seen a case of deformed wing in years and my skewering of drone pupae shows me the mites are under control. Second, because varroa mite levels are out of the treatment consideration loop, I no longer concern myself with watching my bees become increasingly ill before tipping this season’s / year’s suggested EIL level. Third, I could care less even if my mite levels were high. In fact, I would be happy to find they were as it would confirm what I’m doing is working by a mechanism other than killing mites. Fourth, I’m exposing my bees to the same or less OA than I would if I was using currently acceptable OA vapor treatment schedules. Fifth, I’m allowing more time between treatments which lessens the possibility of miticide or antiviral resistance. Sixth, after seeing many new beekeepers struggle with the myriads of options for mite assessment, the complexity of understanding mite counts during different seasons, and the best choice of miticide for each time of year and temperature, what a gift it would be to simplify this process. Seventh, my bees stay healthy and productive all year. Gone is the yo-yo of cleaning them up only to let them fall to approaching colony collapse before a lifesaving series of treatments. That yo-yo isn’t healthy living. We don’t allow diabetics to go into diabetic coma before treating them nor do we allow HIV patients to live with high viral loads. No, we manage these illnesses rather than wait for a crisis to develop. We should keep in mind that our colonies don’t die from the mites they die from high viral loads.

How is this working? My supposition is that I am killing viruses (or a subset of the many virus types) directly, thus bypassing the need for vector (mite) control. Another possibility is I am interrupting the relationship between the virus and the mite – to the mite’s detriment. But to be honest, I don’t know. It could be something entirely different that I haven’t considered. I’ll continue the effort and will start to compile the research and data I have collected.

This honey season is off to a great start. All supers are already deployed and I’m wondering how I’m going to deal with keeping the bees with enough space now that they’ve gone gangbusters. Cheers!

Brief Update 7/20/2025: I’m just back from my state beekeepers assocation’s summer conference. The talk of mites always triggers some guilt that I have not updated this blog entry in some time. So, the effort continues. I have tried to maintained routine monthly treatments although there was some disruption during a personal health event. The success of healthy bees continues with minimal losses. It is rewarding to have a near perfect survival rate in the midst of record national losses in the US. I don’t get to as many conferences as I used to but with those I have shared this effort with, the idea that there is a possibility that I am simply keeping the viral threshold below the point of illness development. Randy Oliver wrote some time back that at a certain mite count within a colony they enter tipping point after which they are doomed to colony failure. I think this is a valid explanation – that the viral threshold is possibly being held in check. By a little or a lot is unknown. If you have ideas let me know. larrycoble@bellsouth.net

The Rule of 72 and Mite Control

27 Friday Aug 2021

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The rule of 72 and mite control.

The rule of 72 is a financial rule of thumb that says that 72 divided by an interest rate will tell you how long it takes for any given amount of money to double.

There are a lot of factors involved but this is also true with many other things in life. For example, we could determine a similar calculation for mites in honey bee colonies.

How is this relevant? The relevance is in the doubling effect. A financial planner will tell you to start saving early for this reason. No matter how much, or little, it matters to start early. Why? To get more doublings.

Your first year’s savings may take 7 years to double. That may be doubling from $1000 to $2000. Not much in the big picture of retirement, huh? But remember there’s another $1000 for each year you saved after your first year. And so it goes. Compounding takes effect and the total grows.

In ten years lets say you have$15,000. That $15,000 doubles in another 7 years plus any additional you have added. By the second doubling you’ll start to see the effects of compound interest.

So, here’s the kicker. By the time you are ready to retire, let’s  say you have $500,000. That’s great but what if you had started 7 years earlier? Think about this. The answer is you’d have another doubling in the equation. That’s right, $1,000,000. The big One Million. Or an additional $500,000 in just seven years. Crazy huh?

And to the point of this post. A mite population has a rule of 72 which can be calculated by it reproductive rate. What does that mean when it comes to mites? It means, just like the rule of 72 and money, it isn’t the first doubling that kills the colony, it’s the last doubling. Now doesn’t this explain some things that sometimes seem unexplainable? Like sudden colony crashes and what appears to be abscondings? That last doubling is simply overwhelming. The viral load transmitted by the mites becomes unsurvivable by the bees. Of course, with bees, the rule of 72 with mites in beehives has a limiting factor – the survivability of the bees.

On my Varroa Soapbox, Understanding Varroa Risk by sassafrasbeefarm

06 Tuesday Jul 2021

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It’s no mystery that Varroa mites are the single most problem facing honey bees and leading to large percentages of colony deaths a year.

Understanding Varroa Risk. We either understand the enemy or he defeats us. The good news is, once understood I can understand the mite’s weaknesses and vulnerabilities. Conquering the mites means I can enjoy my bees much like generations of beekeepers before me enjoyed their bees. In addition, my bees perform better, make more honey, make more bees, and I don’t have the number of odd, random incidents occur in the apiary. All this results when we perform one management task – Varroa assessment, management, and control.

View the video below by Meghan Milbrath at Michigan State University for an excellent review of understanding the Varroa risks and assessing Varroa in your colonies.

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Mite Treatments by What Should I Be Doing With My Bees This Month?

02 Thursday Aug 2018

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Mite treatments will be the hot topic for all beekeepers very soon. Look at the graph above about the bee and mite population and the timeline. The Varroa population lags the bee population, up until early September. Then the mite population keeps increasing as the bee population goes down. This high infestation of mites damages the bees physically and also exposing honeybees to viruses. This high infestation of mites is what kills honeybee colonies.   Beekeepers need to stop this rising mite population during the month of August before the Varroa population explodes. Looking at the graph one can see there is a sharp rise in the month of August in the mite population. Treating colonies in September in many cases is too late. The bees may be so damaged by the rising mite population that they cannot recover.

Read the full article at:  Mite Treatments — What Should I Be Doing With My Bees This Month?

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Alcohol wash to get a mite count in a beehive by Southeastern Indiana Beekeepers Association

22 Sunday Jul 2018

Posted by in bee health, beekeeping, chores, inspections, management, mites, varroa, varroa destructor, varroa mites

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This gallery contains 5 photos.

This is an excellent article on assessing mite counts in your beehives. Thanks to J.Morgan, Karen Ferguson and SIBA for …

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Rainy day beekeeper rambings

29 Monday Jan 2018

Posted by in beekeeping, varroa, varroa destructor, varroa mites

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I posted this last year and, with the start of our season coming soon, I can’t help but repost. I few years ago I assessed my colonies preseason and found they needed a mite cleaning. The difference in their appearance and performance was notable. They were the prettiest bees that spring – vigorous and prolific. Since then I make a point of getting my bees off to a good start early in the spring buildup. Enjoy.

To a carpenter with a hammer everything is a nail. And so it is with me. Registered Nurse with close to 30 years of inpatient hospital unit management, a few graduate level Public Health courses, and 60 years of observation. And so everything looks like a health care management problem (well not everything). Anyway, I thought I’d preface the following comments with a warning that this is just my perspective.

There is a beekeeping saying, “Take your losses in the Fall.” That doesn’t necessarily mean let them die. It typically means combine hives as needed. The economist in us tries to take the least hit possible and combine all of the weaker hives thus at least salvaging one hive out of the mess. My limited experience has been that combining 2 or even 3 weak colonies in the fall still results in a loss. Better to add each of them to a strong hive and take the hive numbers hit right then in the fall. But from a public health or infectious disease standpoint how can we do this safely? If the queen is simply weak that’s one thing, but if an infectious agent or Varroa is the issue you may be causing yourself more anguish by combining an infected hive with a good strong colony. For example, if you were in a hospital room how would you like it if the person in the next bed was being admitted because he/she was weak with a highly infectious disease? Hey, anyone want to share a room with a TB patient? Back to beekeeping… My beekeeping answer is to treat first, pinch the queen, then combine them and even then only if I suspected they were not sick. If they appeared to have succumbed to an infection and are in steep decline then I wouldn’t add those sick bees to another hive, period.

I got to the point of cringing with every Varroa lecture at conferences. But somewhere along the way after looking at the evidence left in my own combs, hives, and other symptoms, I became convinced of a few things. Varroa explains most of the unexplainable. I think successful beekeepers treat early and often. Nowadays, if a hive crashes, I suspect Varroa first. Yeah, maybe they absconded but it was probably secondary to Varroa infestation. Maybe they were robbed but it was probably after they became weak and crashed due to Varroa. I believe Varroa to be the primary cause in most cases. The other events are secondary but that’s what we can see so that’s what we believe happened. We humans are visually oriented to a fault.

But how does it happen so fast you may ask? Ever worked on a hospital ward or lived in a dormitory type housing situation where a flu outbreak occurred? How many sick individuals did you see prior to the epidemic putting everyone in the bed with symptoms? Probably just a few. That’s how it happens. A few sick individuals carrying a potent virus and BAM! Overnight everyone is vomiting with fever and diarrhea. The viri take over and, in the case of bees, a seemingly healthy colony crashes suddenly and we find ourselves perplexed. But why are we perplexed, have we not seen the flu virus in humans close schools? Or cruise ships turn around to return to port after a sudden virus puts all of the occupants in their cabins too sick to continue. Have we been too long without a world plague to have forgotten the infectious disease process?

If you’ve ever read a death certificate it states cause of death. It also allows the physician to state medical factors affecting death. So, cause of death may say “esophageal hemorrhage” but the medical factors might state, “chronic alcoholism.” And so it is with Varroa. Cause of death is “robbing” or “abscond” while the chronic illness would be listed as “Parasitic Mite Syndrome with high virus loading.”

Moving on, so when a colony crashes and robbers come in to clean up the honey guess who takes home something they didn’t ask for? Your other colonies, that’s who. Once the robbing starts the Varroa get distributed among the other hives.

First, in my opinion, you may not want to get into beekeeping if you’re not willing to treat for Varroa and use IPM methods – it’s just too difficult. But then, that’s me. I also take my kids to the doctor when they are sick and don’t let my dogs walk around with ticks in the hope they build a resistance. If you want to be treatment free at least give the bees a chance and buy property 5 miles away from the next closest beekeeper, get clean survivor bees to start, aggressively utilize IPM methods such as screen bottom boards, splits, queen caging, small cell, sugar shakes, and artificial swarms. You’ll be extremely  busy but I do believe it can work for some people. For others it becomes an exercise in frustration and disappointment.

Me? I’m going to treat them early and often after a preseason mite level assessment to establish a baseline. I also monitor mite counts post treatment to ensure the treatment was effective. As a primary offense to prevent outbreaks, I treat every spring before honey supers go on the hives. Then, typically, I do a series of 3 weekly OA treatments in June after pulling supers. During the long hot summer, if a colony starts to weaken I treat that single hive after assessment. If a hive collapses and gets robbed everyone gets a treatment. During December broodlessness everyone gets a single vaporization or dribble. I primarily use OA but I may replace one of the seasonal treatments above with a different method. That’s the two pronged plan of 1) Primary preventative treatment and 2) Aggressive Secondary post infection treatments. That’s what you do when you visit your health care provider – expect preventative measures first, and predictable, effective treatment when you get sick.

Hey, look at your hands right now. How many bacteria and viri do you see? Count them. You can’t but if you get sick you may have wished you had washed your hands a little more frequently. Prevention first, but if you get sick take your medicine!

It’s viri spread by Varroa killing our bees. You don’t see the viri, rarely see the mites that spread the viri, and frequently don’t see the symptoms until it’s too late. Good luck managing your bees’ health.

Varroa Mite Treatments

05 Tuesday Dec 2017

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I’m out in the bee yard vaporizing oxalic within the hives to kill Varroa mites today. Oxalic Acid is harsh on humans and I think it probably isn’t exactly kind to honey bees either although they seem to live on the acid side of the ph scale. I’m reminded though, as I vaporize the oxalic acid within each hive, of a time my son Danny had a nasty wart on his foot. We had tried everything, night after night, to remove it. Finally Danny agreed to go to a podiatrist . He thought it was going to be cut off and he was good with that. Instead the doctor applied a strong acid for a couple hours. Over the course of the next week or so it was basically blistered and burned in appearance. We felt badly for Danny but he was okay with it. He wanted it off. Anyway, applying oxalic acid to the bees kind of reminds me of the same. I hope they appreciate the mite removal.

Kick ’em when they’re down by The Apiarist

30 Thursday Nov 2017

Posted by in beekeeping, varroa, varroa destructor, varroa mites

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Below is an excellent article by David the Apiarist on understanding the varroa mite population cycle as relates to management of Varroa mites. Understanding the pest is key to maximizing the impact of the treatement. I’ve chosen to crosspost it on this date to benefit my readers in the Midlands of South Carolina as we enter the period of time when the presence of brood is at it’s yearly low. References to the Eagles and Don Henley are entertaining as well.

Why bother treating colonies in midwinter to reduce Varroa infestation? After all, you probably treated them with Apiguard or Apivar (or possibly even Apistan) in late summer or early autumn.

Is there any need to treat again in midwinter?

Yes. To cut a long story short, there are basically two reasons why a midwinter mite treatment almost always makes sense:

  1. Mites will be present. In addition, they’ll be present at a level higher than the minimum level achievable, particularly if you last treated your colonies in late summer, rather than early autumn.
  2. The majority of mites will be phoretic, rather than hiding away in sealed brood. They’re therefore easy to target.

I’ll deal with these in reverse order …

Read the full article at: Kick ’em when they’re down — The Apiarist

Werewolves Not Vampires by The Prospect of Bees

26 Sunday Nov 2017

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Oh, had we but seen this video a few days earlier, in time for Halloween! A three-minute thesis competition is a contest for PhD students in which they condense their thesis into a three minute presentation comprehensible to an intelligent audience lacking any background in the research area. Doctoral candidate Samuel Ramsey was the winner […]

Read the complete article at: Werewolves Not Vampires — The Prospect of Bees

Beekeeping Vocabulary – “V” is for…

12 Sunday Nov 2017

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Image of Varroa Mite supplied by Kika De La Garza Subtropical Agricultural Research Center Weslaco, Texas, USA {{PD-USGov-USDA-ARS}

 

Today’s beekeeping vocabulary word is, “Varroa.”

From Wikipedia:

Varroa is a genus of parasitic mites associated with honey bees, placed in its own family, Varroidae.[4] The genus was named for Marcus Terentius Varro, a Roman scholar and beekeeper. The condition of a honeybee colony being infested with Varroa mites is called varroosis (also, incorrectly, varroatosis).

Varroa mites are recognised as the biggest pest to honeybees worldwide due to their ability to transmit diseases such as deformed wing virus to larval or pupating bees, resulting in death or severe deformity of the pupae.

Varroa mites feed off the bodily fluids of adult, pupal, and larval honey bees, and may carry viruses that are particularly damaging to the bees (e.g., deformed wings, and IAPV), and accordingly they have been implicated in colony collapse disorder. Research has indicated that alone, neither Varroa mites nor deformed wing virus are particularly deadly, yet together they can pose an incredible risk to colonies.[5][6]

Varroa mites were first discovered in Java about 1904,[7] but are now present in all honey bee populations except Australia, Isle of Man and northern parts of Norway. They were discovered in the United States in 1987, in New Zealand in 2000,[8] and in the United Kingdom in 1992 (Devon).

Bee-breeding efforts to develop resistance against Varroa are ongoing. The USDA has developed a line of bees which uses Varroa-sensitive hygiene to remove reproductive mites. This line is now being distributed to beekeepers to be used as part of their integrated pest management programs.

Source and to read more: Wikipedia

Participate in the First Ever Mite-A-Thon by IPM in the South

15 Friday Sep 2017

Posted by in beekeeping, varroa, varroa destructor, varroa mites

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A single Varroa mite infestation can quickly spread and devastate hives across an entire region. Early detection and control are key to supporting honey bee health and preventing catastrophic infestations. That’s why the Honey Bee Health Coalition, which has developed essential Varroa mite resources, is proud to support the first ever Mite-A-Thon.

The Coalition urges beekeepers to participate in this exciting and free event by visiting www.pollinator.org/miteathon.

The event, which will take place from Saturday, September 9, to Saturday, September 16, will help collect vital data on Varroa infestations across North America and help beekeepers and others confront these problematic parasites.

Participants will test the level of mites present in their hives using a standardized protocol utilizing two common methods of assessment — powdered sugar roll or alcohol wash — and upload their data at www.mitecheck.com, including location, total number of hives, number of hives tested, local habitat, and the number of Varroa mites counted from each hive.

Beekeepers and others also can learn more about Varroa mites and best practices to monitor and control them by visiting honeybeehealthcoalition.org/varroa/.

The Mite-A-Thon is supported by the North American Pollinator Protection Campaign (NAPPC), Pollinator Partnership, and numerous partners, including the Honey Bee Health Coalition.

via Participate in the First Ever Mite-A-Thon — IPM in the South

ProVap110 Oxalic Acid Sublimator by sassafrasbeefarm

26 Sunday Feb 2017

Posted by in beekeeping, chores, management, mites, pests, product review, varroa, varroa destructor, varroa mites

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Product Review:

For Varroa mite control, I sprung for a ProVap110 this year. I put it through the paces this week and thought I’d report on it here.

View Video Here:

Disclaimer first: Yes, Larry of OxaVap is a friend of mine. We met at a South Carolina Beekeepers Association conference several years ago and hit it off talking bees non stop for the duration of the conference. This was all before oxalic acid was approved for use in the United States. Larry told me then it would be the next big deal in Varroa mite control and apparently he was right as it was approved a couple years later. (Larry also told me where U.S. beekeepers were already ordering vaporizers from across the border in Canada.) Anyway, Larry and I always look forward to conferences and hanging out, telling bee stories when we can.

Before getting the ProVap110 I was using two Varrox, pan type ,vaporizers. Using two really sped up my mite treatments. Duh, twice as fast, right? No, don’t ask me how but everything moved faster and down time between hives was less so I really think I was doing the job in less than half the time than with one.

Recently, Larry suggested I needed to try the ProVap110 but I was resistant due to the issue of needing AC current. He said that most inexpensive car/truck inverters would do the job as it only used 250 watts and 2.2 amps. I checked and Harbor Freight had an inexpensive inverter. But I really wanted to be able to treat without having to drive my truck into sometimes muddy out yards. Larry assured me that a long extension cord run would not be a problem but I resisted and bought a small WEN 1800watt generator. I do plan on buying that inverter as well but the WEN1800w is under 50 pounds and, so far, I really like it and don’t have to worry about getting my truck stuck in a muddy out yard field while vaporizing mites.

One morning this week I oxalic acid vaporized 32 hives in about an hour and 15 minutes. As with the old Varrox, you still have the setup time of placing IPM boards under screened bottom boards to help seal the hive as well as a damp dishcloth across the entrance. I left the WEN1800w generator in the back of my truck and used a 50 ft extension cord. The extension cord had no noticeable effect on the operation as the ProVap performed exactly as the enclosed paperwork stated it would. I will use a 100 ft extension next time to see if that has any effect. The ProVap110 took about 2 to 3 minutes to reach its operating temperature of 230C. The unit adjusts to maintain that temperature throughout its use. I’ll place a link to a video in this post for those who have not seen how it operates. Basically, after it reaches its operating temperature a measured amount of OA is placed in a cup and attached to the ProVap110 while inverted. The nozzle is inserted into a 1/4″ predrilled hole in the hive body and the unit is spun around to its upright position causing the OA to drop into the 230C pan. The temperature readout dropped to approximately 208C when the OA came in contact with the heating unit and immediately began its rise back to 230C. Within about 20 seconds the temperature had returned to 230C and I removed the unit from the hive. An additional “cup” is provided so the user can prepare the dose for the next hive during the 20 second wait. And so it goes hopscotching down the row of hives.

Some things I learned are: 1) Hole placement is more critical than I first expected. I had used a homemade template based on the instruction sheet and some of the holes were drilled into handholds which caused me to have to hold the unit in place instead of leaving it to prep the next dose. The instructions say drill the hole 3 to 4 inches up from the bottom . I will drill future holes below the handholds in the lower box – if you use cleats drill well below. You want the vapors to circulate readily once inside the hive so make the hole in that area where the frames are narrow (lower half) to allow for the bees to move around the frame. 2) The tube that sends the vapor into the hive is copper and about 3/4″ in length. That makes sense since it is going into a hive body with a thickness of 3/4″. Longer and it could bottom out on a frame inside. Unrelated to the tube length but I’d like the tube to be made of a harder metal than copper if possible – I am uncomfortable with the possibility of bending the copper tubing. 3) You will need an acid/vapor PPE mask as you will be in close proximity of the OA vapor. There is no getting around this. I currently use a 3M 7502 mask with organic vapor/ acid gas filters – $13.99 on Ebay, and non vented safety goggles – $7.99 Ebay. The mask worked great and I never even got a whiff while standing behind the hive administering the OA vapor. (more on this later)

Some of the nice things about the unit are: 1) Its speed. I usually just stood there behind the hive for 20 seconds and let it do its thing. 2) The plume of vapor into the hive is thick and sudden. The bees don’t have the “warning time” they did with pan type vaporizers to start fanning. Bang, it’s in there and done. Most of the hives didn’t object any more than they did with the pan vaporizer but a couple did. All hives settled down soon afterwards. 3) The almost constant 230C temperature ensures the OA is properly sublimated. I always suspected the gradual warming of the OA with the pan vaporizers may have wasted some of the OA as it was evaporated, boiled off, or was otherwise consumed instead of sublimated thus diminishing the dose. The ProVap110 ensures the OA always hits the pan at exactly 230C. 4) I often lose my biggest and strongest hives over the winter. I’ve always suspected it might be related to inadequate OA treatment reaching the upper boxes. Now I can treat the hive via a 1/4″ hole placed anywhere, in any box, instead of just underneath the hive. And don’t worry about drilling 1/4″ holes in your woodenware, the bees will propolize it soon enough or you can use a golf tee or dowel rod to plug. 5) It would be nice to have a half dozen of the “caps.” to prepare in advance. It’s not essential; that’s just my OCD speaking.

General comments: Most efficient use would necessitate a planned layout of the hives in the bee yard. If you scatter your hives around here and there you’ll waste time in transit. I have basically three different zones in my home yard. This meant driving the truck to three different positions and repositioning the drop cord each time. I think keeping your hives within a 100 foot radius and using a 100 foot drop cord might be ideal. Having plenty of IPM boards available is also a great time saver as transferring them hive to hive is a time waster. Luckily I have plenty to use in case of a severe winter but others may not. The hives with solid bottom boards were easiest to treat.

Now, here’s an interesting thing: The visible escaping particulate using the ProVap110 was noticeably less than when using pan type vaporizers. I can’t really account for why this is other than the bees don’t have the 2 – 4 minutes to start fanning before the deed is done. I actually used the ProVap110 in the first two hives and thought, “Did it work?” So I loaded the ProVap110, held it downwind, and flipped it to see if it was sublimating the OA. Yes, it was working and it’s done in about 20 seconds. If you look at the video, at the end the guy does exactly this and you can see how thick the plume is and how fast it comes out. Anyway, my point is, there appears to be less particulate escaping the hive than with pan vaporizers – and that’s a good thing!

Cleanup is a breeze. A little water to wash out the areas where the OA comes in contact was quick and easy. The unit itself cools off quickly when unplugged which is good and bad. Good for safety once you are done but moving into different bee yard zones meant having to wait the 2 – 3 minutes for the unit to return to operating temperature. I’m convinced I can shave 30 minutes off my first effort implementing some of the changes mentioned above.

I am satisfied with the unit over the pan type vaporizers for a few reasons: time efficiency, proper sublimation, flexibility in selecting placement of the area the OA is administered, and ease of use. I’d recommend it to anyone that starts to feel that pan-type vaporizing is taking too much of their bee management time that could be better spent more productively.

Addendum August 31st, 2017: After having used the ProVap100 for multiple yard treatments I thought I’d comment on a couple items I hedged on in my first review (above). First, use of multiple extension cords makes no noticeable difference in either warm up time or time to sublimate the oxalic acid. I am now using two fifty foot extensions cords and I get the same excellent performance as with one. Second, After having a problem with my gas powered generator I purchased an inexpensive 400 watt inverter at my local Harbor Freight store for ~ $23.00 USD. Using this as my power source the ProVap100 performed again without any degrading of performance. At $23.00 versus what I paid for the gas powered generator I’d opt for the inverter first unless there was an issue with access to the bee yard. Third, Thus far this year I have not lost my biggest hives post nectar flow and during the Varroa buildup as I have in previous years. I am unable to say that positive outcome is a result of the ProVap100 but I suspect it is a contributing factor. I remain very happy with the unit and from emails and messages I have received from people that have also purchased one they are likewise happy with the efficiency and ease of use of this unit.